1. Other than the sun, planets, and moon, what other objects are found in the Solar System?

2. In this lesson, we are going to be comparing comets, meteors, and asteroids which are found in the Solar System. Known as NEO’s
Instructional Approach(s): The teacher should read the slide to the class.

3. Essential Question: What is the difference between a comet, meteor, and asteroid?
S6E1e. Ask questions to compare and contrast the characteristics, composition, and location of comets, asteroids, and meteoroids.

4. Comets

5. We know that comets are composed primarily of many varieties of ice, including water, carbon dioxide, methane and ammonia ice. There is also a bit of dirt mixed in, usually in the form of carbon. This makes them appear as dirty snowballs, which is actually the name for the model that is proposed for their compositions. The best way to think of a comet is that it is like a big chunk of ice, dirt and slush that gets stuck to the wheel well on your car during the winter.

6. Comets
Comets may appear as huge objects in the sky, but they are typically only about 10 km in diameter, much smaller than many other objects going around the Sun. This core or nuclei is how most comets appear when located in the outer solar system (beyond Jupiter's orbit).

7. Composition: hydrogen, carbon & nitrogen compounds
Hale-Bopp
Comet Wild 2

8. Found in Kuiper belt and Oort Cloud
Comets -- large chunks of frozen gases and solid particles
Found in Kuiper belt and Oort Cloud
Due to perturbation of orbit, enter inner part of solar system , UV from Sun ionizes the frozen gases, and they fluoresce. Tail made up of glowing gases and solid particles that reflect sunlight.

10. Comets thus the tail is always facing away from the Sun. Solar wind
forms the tail,
thus the tail
is always facing
away from the
Sun.

11. Comets
When a comet nears the sun, some of it melts and forms a long tail (gases in the comet are vaporized by the sun)
When a comet moves farther away from the sun, the tail disappears
show the animations of a comet traveling in the solar system to reinforce the concepts.

12. Comets Tails
Two tails are usually seen. These include the gas tail (also called the ion tail), which is made up of material that is blown straight back by the solar wind. This is generally made of the really lightweight gases. Within the gas tail you find stuff such as water vapor, CO, CO2, N2, ammonia and methane gases and particles.

13. Comet Tails cont.
The gas tail has a rather ragged appearance and is sometimes rather bluish. It is always pointed directly away from the Sun. The other tail, the dust tail, is made up of heavier particles and is not as greatly affected by the solar wind. It has a very fuzzy appearance, often looking rather yellow-ish or whitish.

14. Location
The first of these regions is what is known as the Kuiper Belt, a band of comets similar in many ways to the Asteroid Belt found in the inner Solar System. Comets originating in this region have relatively short orbital periods and orbit the Sun in roughly the same plane as do the planets. The second region, called the Oort Cloud, is a region farther out than the Kuiper Belt and is essentially a spherical shell.

15. Facts about comets
Sometimes comets are referred to as “dirty snowballs” or “cosmic snowballs”. This is because they are composed mostly of ice, rock, gas and dust.
Comets orbit the Sun in elliptical paths – just like the planets. The path of a comet though is far more elliptical than that of any planet.
A comet has four components: a nucleus, a coma, a dust tail and an ion tail.
The nucleus of a comet contains the vast majority of its total mass.

16. Comet facts
Comets have a halo when they move close to the Sun. What happens is the solar radiation vaporizes the ice and gas gas in the comet into a halo around it. The halo is known as the comets coma.
The ion tail of a comet is the result of solar winds that blow the gas particles directly away from the Sun.
A comet’s dust tail is a trail of dust and rocky material that is left behind as it moves along its orbit path.

17. Comet facts
Comets are believed to originate in one of two regions – the theorized Oort Cloud, or the Kuiper Belt found beyond the orbit of Neptune and the dwarf planet Pluto.
The Oort cloud is an outer region of the Solar System 50, ,00 times the distance from the Sun to Earth that is believed to contain dormant comets. Some of the comets that originate here have orbits lasting millions of years.

18. Comets facts
The Kuiper Belt is ring of dormant comets located just beyond the orbit of Neptune. The comets originating here have orbits lasting hundreds of years or fewer.
The most famous comet is Halley’s Comet. It has been observed since at least 240 B.C. Its orbit makes it visible from Earth every 76 years. It was named after the British astronomer Edmond Halley.

19. Asteroids
Instructional Approach(s): Introduce Asteroids

20. Asteroids…Rockin’ Around made of
Asteroids are LARGE made mostly of rock — with some composed of clay and silicate — and different metals, mostly nickel and iron.
They range from just over ½ a mile (1km) to a few hundred miles in diameter (diameter = how wide across)

21. Asteroid
Most asteroids are located in an area between the orbits of Mars and Jupiter called the Asteroid Belt.
Why are they located there?
The gravity of Jupiter might have kept a planet from forming in the area

22. Instructional Approach(s): The teacher should use the image to reinforce the location of asteroids.

23. Asteroids……Rockin’ Around
The Anatomy of Asteroid Names
Sometimes it seems that astronomers enjoy picking nonsense names for the objects they study. What person on the street would guess that "2000 QW7" is a fascinating space rock? Nevertheless, there is a method to this naming madness.
So many new asteroids are discovered each month that astronomers need an efficient way to catalog them. The first part of "2000 QW7" is simple -- it identifies the year of the asteroid's discovery (2000).
Then comes "QW7." The first letter tells us that the object was identified during the second half of August. Each half-month is identified with a letter of the alphabet. January 1st-15th = "A"; January 16th-31st = "B"; August 16th-31st = "Q", etc. The letter "I" is omitted in this system.

24. Asteroids……Rockin’ Around
The second and third characters "W7" are a shorthand way of counting the number of asteroids found during the 2nd half of August The first asteroid discovered was "2000 QA"; the second was "2000 QB;" The second letter cycles through the alphabet until it reaches "Z" and then it goes back to the beginning with an extra number. So, the 26th asteroid discovered during the second half of August 2000 was "2000 QA1". Remember that "I" is omitted, so "A1" corresponds to the 26th asteroid, not the 27th. This means that 2000 QW7 was the 197th asteroid found in the second half of August 2000!

26. Meteorite is a meteoroid that hits the earth’s surface
Meteoroid is a “space rock” that is still in space
Meteor is a meteoroid that burns up in the earth’s atmosphere (Shooting Star)
Meteorite is a meteoroid that hits the earth’s surface

27. Meteors…Shooting Stars
Meteors are also called shooting stars
Meteors are small pieces of space debris pulled into Earth’s atmosphere by gravity.
Meteorites are metallic rocks broken off from asteroids and comets
Meteors fall to Earth at speeds from 22,000 MPH to 64,000 MPH (8x shuttle speed)
You Can Buy Meteors-

29. Meteors…Shooting Stars
Most meteors are only as big as a grain of sand.
Most burn up while entering Earth’s Atmosphere
However………………
They can be bigger. Craters in the Earth and ones studied below the surface show that one about the size of a house landed about 250,000 years ago! Is that what killed the dinosaurs???

30. Meteors…Shooting Stars
How can something as small as a grain of sand light up so brightly?
Entering the Earth’s atmosphere so fast creates a lot of friction. The friction causes them to heat up and give off light.
The light trail may stay in the sky for up to 30 minutes and end with a “POP”.
REALLY bright meteors are called
FIREBALLS

31. Meteoroid, Meteor, Meteorite
Meteoroid, Meteor, Meteorite? The difference is just based on where the rock is located when you are describing it. So the difference is just based on where the rock is when you are describing it

32. Comet, Meteor or Asteroid? Explain how you know.

33. What’s That Up In The Sky???
COMETS
ASTEROIDS
METEORS
Made of ice-have tails
Made of rock and metal
Made of rock and metal/ iron & nickel
Stay in space
Fall into Earth’s atmosphere
Orbit the sun
Gravity pulls to Earth; they burn up as they fall

34. Hollywood gets in the act:
Meteor
Night of the Comet
Asteroid
Armageddon
Deep Impact